/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * IteratedLovinsStemmer.java
 * Copyright (C) 2001-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core.stemmers;

/**
 * <!-- globalinfo-start --> An iterated version of the Lovins stemmer. It stems
 * the word (in case it's longer than 2 characters) until it no further
 * changes.<br/>
 * <br/>
 * For more information about the Lovins stemmer see:<br/>
 * <br/>
 * Julie Beth Lovins (1968). Development of a stemming algorithm. Mechanical
 * Translation and Computational Linguistics. 11:22-31.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- technical-bibtex-start --> BibTeX:
 * 
 * <pre>
 * &#64;article{Lovins1968,
 *    author = {Julie Beth Lovins},
 *    journal = {Mechanical Translation and Computational Linguistics},
 *    pages = {22-31},
 *    title = {Development of a stemming algorithm},
 *    volume = {11},
 *    year = {1968}
 * }
 * </pre>
 * <p/>
 * <!-- technical-bibtex-end -->
 *
 * @author Eibe Frank (eibe at cs dot waikato dot ac dot nz)
 * @version $Revision$
 * @see LovinsStemmer
 */
public class IteratedLovinsStemmer extends LovinsStemmer {

    /** for serialization */
    static final long serialVersionUID = 960689687163788264L;

    /**
     * Returns a string describing the stemmer
     * 
     * @return a description suitable for displaying in the explorer/experimenter
     *         gui
     */
    public String globalInfo() {
        return "An iterated version of the Lovins stemmer. It stems the word (in " + "case it's longer than 2 characters) until it no further changes.\n\n" + "For more information about the Lovins stemmer see:\n\n" + getTechnicalInformation().toString();
    }

    /**
     * Iterated stemming of the given word. Word is converted to lower case.
     * 
     * @param str the word to stem
     * @return the stemmed word
     */
    public String stem(String str) {

        if (str.length() <= 2) {
            return str;
        }
        String stemmed = super.stem(str);
        while (!stemmed.equals(str)) {
            str = stemmed;
            stemmed = super.stem(stemmed);
        }
        return stemmed;
    }

    /**
     * Runs the stemmer with the given options
     *
     * @param args the options
     */
    public static void main(String[] args) {
        try {
            Stemming.useStemmer(new IteratedLovinsStemmer(), args);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
